Expect climate ‘surprises,’ UA expert says

The director of UA’s Institute for Environment and Society issued the warning Friday with two other experts during a symposium to address climate change.

The debate on why the world is warming has ended, according to the presenting scientists. Now that it’s established that humans at least partially responsible, they say, it’s critical to focus on how climate change might affect life in the 21st century and what can be done to manage the impacts.

But while society anticipates changes, it must also be aware that the predictions are shrouded with uncertainties and likely underestimated, the scientists said.

“Be prepared for surprises,” said Jonathan Overpeck, director of the University of Arizona’s Institute for Environment and Society, one of three speakers at the symposium, titled “Global Change and Paleoecology: Ecological Responses to Environmental Change.”

Although scientists can forecast potential effects of climate change, such as sea-level and temperature rises, there are also unknowns and degrees of uncertainty in model projections, he said.

“There’s no spirit of ecosystem’s future to tell us what will happen,” Stephen Jackson, director of the University of Wyoming’s department of botany, said during the symposium. However, he added that “ghosts of ecosystems past” do provide scientists with evidence of potential impacts.

“The good news is that climate change is nothing new. It’s part of the world we live in,” he said.

But the bad news is that a time of climate change is not a good time to be around, Jackson said.

There will be winners and losers, he said, meaning that the changes will be good for some species and bad for others.

As far as what species will benefit and what species will lose, there are “no guarantees,” he said.

Although climate variation is not unique to our planet, human activities have intensified its impact and, thus, its consequences, they said.

Stacking human activity on natural variation will likely have grave ecological impacts, including the extinction of species that have survived climate change in the past.

McLachlan offered a simple yet powerful metaphor about the threat of global warming’s impact and what needs to be addressed.

Climate change is like an oncoming train, he said. On the train’s tracks are babies in carriages, representing aspects of ecology that are in danger of being struck.

What society must now focus on is evaluating what resources and species are most at risk and develop strategies to get them farther down or off the track, he said.

“But keep in mind we’re driving the train,” he added.

He noted that humans influence the train, but said that at this point, the world has already committed itself to climate change and must face it challenges even if our species were to stop contributing.

High levels of carbon dioxide produced by humans will have a long lifetime in the atmosphere, said Overpeck.

“We can’t magically cool the Earth down,” he said, foreshadowing that impacts will persist for hundreds to thousands of years into the future.

“What we’re talking about is for keeps.”

Overpeck’s forecast
Although Overpeck expressed that there are uncertainties, many of the consequences associated with global warming that scientists have predicted are already occurring, especially in regions like the Southwest, he said.
Major impacts of climate change, according to Overpeck, include:

An increased chance of extreme drought, especially in regions such as the Southwest.

Major landscape disturbances such as forest fires will likely become routine.

There will be a need for society to become more careful managing its resources – climate change could me much more dramatic than expected.

UA represented
Not only did Jonathan Overpeck cite the work of other UA researchers, there are other speakers representing UA at the American Association for the Advancement of Science’s Annual Meeting in Chicago.
Other UA faculty members who will be presenting this weekend are Regents Professor Vicki Chandler, on “Epigenetic Silencing Across Generations?”; Biosphere 2 director Travis Huxman, on the “Future of the Sonoran Desert”; and professor Michael Sanderson, on “Computational Challenges in Building the Phylogeny of Plants.”

About the reporter
Evan Pellegrino is a NASA Space Grant intern at the Arizona Daily Star. He is reporting from the AAAS’s Annual Meeting as a student journalist with the National Association of Science Writers.
The meeting is one of the largest scientific conferences in the world.
Thousands of participants have gathered for symposia, seminars and workshops, as well as plenary and topical lectures by some of the world’s leading scientists and engineers.
Contact NASA Space Grant intern Evan Pellegrino at 573-4195 or at epellegrino@azstarnet.com.

Expert: AZ in climate-change bull’s-eye

By Tony Davis, February 18, 2009, Arizona Daily Star

The state’s best-known climate-change expert presented harrowing forecasts for sharply higher temperatures and drier rivers and reservoirs before a legislative committee in Phoenix on Tuesday.
Jonathan Overpeck told the House Environment Committee that:

Temperatures could regularly hit the 130s in Phoenix by the second half of this century due to human-caused climate change. In Tucson, temperatures could periodically go into the 120s by that time, said the University of Arizona scientist in an interview shortly afterward.

A group of researchers meeting at a conference Overpeck attended this week in Seattle concluded that the most likely reduction in Colorado River flows from global warming and drought will be about 20 percent by 2050. A separate study, still under review for publication, will predict a 30 percent chance that Lake Mead and Lake Powell could go dry by 2050 if nothing is done about climate change, he said.

That’s far less severe than the prospect of a 2021 drying of those lakes that came from an earlier study from Scripps Institution of Oceanography researchers. But it’s still a significant threat. “It’s not if it will happen, it’s when it will happen,” Overpeck said.

Various reports indicate Arizona has the country’s fastest or second-fastest warming temperatures and predict that Arizona will warm up and dry faster than any other state.

He warned of an economic calamity if global warming isn’t curtailed. “Once the Central Arizona Project goes dry for one year, our state is dead; people won’t want to live here anymore.”
Larry Dozier, an official with the agency running CAP, said it is trying to avert such a crisis by planning to do cloud-seeding, remove water-sucking tamarisk trees from rivers and search for alternative water supplies.

“We’ve got to spend some money. It will take environmental clearances and political clearances, but if people want water at a rational, affordable price, you can have it,” said Dozier, CAP’s deputy general manager.

But Overpeck, director of UA’s Institute for Environment and Society, said Arizona has one of the country’s best opportunities to combat climate change because of its abundance of solar energy.
Two Republicans on the committee praised his talk but didn’t sign on to all of his solutions to reduce global warming.

The committee will consider legislation to pull Arizona out of a seven-state effort to limit greenhouse-gas emissions from power plants and other sources. Overpeck spoke against the legislation.

The bill targets the Western Climate Initiative, an effort pushed by former Gov. Janet Napolitano that has drawn criticism from many Republican legislators. They have tried unsuccessfully before to pull Arizona out of the agreement, partly on the grounds that Napolitano was wrong to sign the initiative without the Legislature’s backing.

Overpeck spoke the same day that a lobbying group for energy and other business interests released a study warning that the Western Climate Initiative will prolong the recession and will reduce global temperatures by only a tiny fraction of a degree even after a century.

The study, commissioned by the Western Business Roundtable, found the initiative’s greenhouse-gas cap-and-trade plan could “chase away tens of billions of dollars in high-technology investment from the West to other regions” and would “further stress the West’s already strained electricity grid, increasing the threat of potentially catastrophic power outages.”

The climate initiative calls for a system in each state that would limit greenhouse-gas emissions from utilities and other large sources of fossil fuels. Companies that produce fewer emissions than they are allowed to produce could trade those rights to companies producing more emissions than allowed.

Overpeck was a lead author for the 2007 report of the International Panel on Climate Change. It predicted average global temperature increases of more than six degrees Fahrenheit under the fastest growth rate in greenhouse-gas emissions that scientists at the time thought was possible.
Now, greenhouse-gas emissions are growing faster than the report predicted at the time, raising the prospect of dramatically higher Arizona temperatures by mid-century, according to Overpeck.
“Whether it is drought frequency, the increase in temperature or the decrease in soil moisture, we are in the bull’s-eye – the worst in the United States,” Overpeck said.

Overpeck is someone Rep. Lucy Mason, R-Prescott, said she wants to work with in developing policies “toward moving Arizona into the 21st century on renewable energy.” But Mason opposes the state being in the regional climate program, out of concern that having to follow a regional solution would hamper individual efforts made in Arizona to reduce emissions.

Overpeck’s presentation was “direct and to the point,” said Rep. Frank Pratt, R-Casa Grande.
But he said he has not made up his mind on the climate-initiative legislation and finds it hard to decide if global warming is human-caused.

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